<!DOCTYPE html>
<html>
<head>
  <title></title>
</head>
<body>
<style>
  .italic { font-style: italic; }
</style>
<div id="app" style="margin-left: 300px;">
  <p v-bind:class="className" v-bind:title="title">危险勿触</p>
  <button v-bind:disabled="10 + 10 === 20">点击有奖</button>
  <input v-bind:type="'text'" v-bind::placeholder="true ? '请输入' : '请录入'">
  <p :class="className" :title="title">危险勿触</p>
  <button :disabled="10 + 10 === 20">点击有奖</button>
  <input :type="'text'" :placeholder="true ? '请输入' : '请录入'">
</div>
<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.min.js"></script>
<script type="text/javascript">
  let vm = new Vue({
    el: '#app',
    data () {
      return {
        className: 'italic',
        title: '危险勿触'
      }
    }
  })
</script>
</body>
</html>